Anbar Journal of Engineering Sciences (AJES-2009) 71 AJES, Vol. 2, No. 1 Modification of Asphalt Mixture Performance by Rubber-Silicone Additive Taher M.A. Al-ani Anbar University/ Engineering College/ Civil Dept Abstract: This study is the second stage of the paper “Studying the Effect of Rubber- Silicone on Physical Properties of Asphalt Cement”. The present study examines the effect of additives on asphalt mixture performance. Asphalt mixture has been designed by Marshall Method for determining the optimum asphalt content and geophysical properties of mix according to ASTM (D-1559). Rubber-silicone at different percentages (1%, 2%, 3% and 5%) was added to asphalt binder. Six specimens of asphalt rubber silicone mixture (ARSM) for each percentage are prepared and evaluated according to Marshall method. Diametric tensile creep test ASTM (D- 1075) at 60 C o was used to evaluate permanent deformation and modulus of elasticity for ARSM. The study showed that the Rubber-Silicone has more effects on performance of asphalt mixture by increasing the Marshal stability, air voids, and reducing the flow and bulk density compared with the original mix. It also increases the flexibility properties of the mix and this appears from reducing the permanent deformation at test temperature (60C), the reduction percent is about (30 to 70) %. Keywords: asphalt mixture, modification, additives, rubber-silicone, performance 1. Introduction Polymer modified asphalt binders (PMBs) are becoming wider spread in road building to meet today’s high traffic loading. Many efforts are directed towards modifying the asphalt or paving mixture properties to get superior performance and serviceability under local conditions and to economize the construction of pavement [1]. There have been many investigations on polymer modified asphalt binders as counter measure to prevent plastic flow [2]. Modification of bitumen with polymers decreases its temperature susceptibility chiefly by increasing its ring and ball softening point, increases its cohesion and modifying its rheological characteristics [3]. The purposes of modification include: increase the viscosity at the high temperature, increase the flexibility and elasticity of binders at the low temperature, improve the adhesion to aggregates, and improve high thermostability and aging resistance [4]. The aim of this paper is to study the effect of rubber silicon on the performance of asphalt mixture for different percent of added (1%, 2% 3% and 5%) by weight of binder. For this purpose the performance changes were evaluated by Marshall Tests and diametric tensile creep test at 60C o . 2. Review of Literature The properties of asphalt important for its consideration as a paving material are its rheological properties, adhesion, and durability [3]. Since the highway engineer is usually limited in his choice of asphalt source, there is need for a practical way to improve asphalt quality by the addition of modifying ingredients. In this regard it is believed that PMBs may improve durability and wear resistance [6]. Reclaim rubber obtained from used tyres, polyethylene in the form of low density (LDPE), styrene-butadiene-styrene copolymer, latex are used for modification of asphalt cement and test sections were found to perform satisfactorily [5].
Modification of Asphalt Mixture Performance by Rubber-Silicone Additive
Jun 20, 2023
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